Engines, including diesel engines, gasoline engines, natural gas engines, and other engines known in the art, exhaust byproducts of combustion to the atmosphere. Typically, the byproducts are discharged via an exhaust stack that extends vertically from the engine or from an enclosure of the engine. As such, it is possible for precipitation to enter the exhaust stack when the engine is non-operational (i.e., when the exhaust stack is not being pressurized by a flow of exhaust). When the engine is operational, precipitation can also enter at the edge of the exhaust stack where the exhaust flow is weaker. It is also possible for moisture from the exhaust to condense in the passageways of the engine exhaust system as the exhaust cools. Moisture in the exhaust system can negatively impact components of the engine through corrosion (e.g., oxidation, staining, and rusting of interior and/or exterior exhaust passages, etc.) and mechanical interference (e.g., interference with engine valves and/or pistons of the engine). Moisture also may damage various exhaust system elements, such as after-treatment regeneration devices.
One way to minimize the effect of moisture in an engine exhaust passageway is to collect and contain the moisture within a confined area away from potential problem locations, until the moisture can be evaporated and entrained in outgoing exhaust. An example of this strategy is disclosed in U.S. Pat. No. 7,065,961 (the '961 patent) issued to Batten, Jr. on Jun. 27, 2006. Specifically, the '961 patent discloses a moisture trap formed as an integral part of an exhaust stack. In the '961 patent, tapered surfaces in the exhaust stack are provided to direct condensation downward and into a reservoir of the moisture trap. The condensation is retained in the reservoir until the temperature of the exhaust system reaches adequate magnitudes to evaporate the condensation and conduct it out of the exhaust system along with the exhaust gases.
Although the moisture trap of the '961 patent may help to minimize the effect that moisture may have on the associated exhaust system, it may still be problematic and have limited applicability. Specifically, once the moisture has been trapped in the reservoir, it may be difficult to empty the reservoir because the moisture trap of the '961 patent relies solely on the heat of the engine to vaporize and entrain the moisture. In some conditions, the heat from the engine may be inadequate to sufficiently vaporize the trapped moisture. Further, cooling passages are formed immediately external to the exhaust conduit of the '961 patent. These cooling passages may minimize the amount of engine heat transferred from the engine to the exhaust conduit and reduce the likelihood of vaporization.
The disclosed exhaust system is directed to overcoming one or more of the problems set forth above.